Transwikied from- http://lifeafterpeople.wikia.com/wiki/Calgary_Tower
The Calgary Tower is an observation tower in Calgary, Although it is not the tallest structure in Calgary but It's still tall, Taller than the space needle In Seattle.
100 Years after people, The tower corrodes after a century without maintenance, After a century of Negelect, The Antenna looms over and slices a Skyscraper.
300 Years after people, The observation deck of the tower begins to loom over and fall straight down. Only a part of the concrete shaft remains.
500 Years after people, Amazingly, the concrete shaft still stands, although it is covered in vegetation. It is the last human-made structure still standing in what used to be Calgary, but it is not immortal. The Concrete of the structure begins to tumble over cracking and falling down. Nearly all evidence that the city of Calgary ever existed has now disappeared forever.